Numerical simulation and analysis of aerodynamic characteristics of commercial vehicles with different tail fins

Abstract To improve the fuel economy of commercial vehicles, this paper designs two types of commercial vehicle tailfin shapes from the perspective of reducing the wind resistance at the rear of the vehicle, aiming to reduce the influence of the vortex at the rear of the commercial vehicle on the driving performance. Based on the aerodynamic principle, the STAR-CCM+ simulation tool was utilized to simulate the no-tail model, three-surface tail model, and four-surface tail model for the two cases of commercial vehicles with flat compartments and concave compartments, to study the effect of the tail fins of commercial vehicles on the reduction of the tail wind resistance coefficient of commercial vehicles. The results of the study show that the commercial vehicle model with three-side tail fins can reduce the wind resistance by 25.6% in the case of a flat compartment surface and 24% in the case of a concave and convex compartment surface of the commercial vehicle compared to the model without tail fins. In comparison, the four-side tail fins commercial vehicle model only reduces the wind resistance by 22.5% and 16.2% in the same cases. The experiments confirm that the rear wing of the commercial vehicle can effectively mitigate the rear wind resistance. The three-surface tail model has better stability than the four-surface tail model, and the optimization effect is better when the side compartment surface is flat.